INVESTMENT OPERATIONS - Variable Interest Entities (Details)	12 Months Ended
Dec. 31, 2017 USD ($) reinsurer	Dec. 31, 2016 reinsurer
Red Mountain
Variable Interest Entities
Number of wholly owned subsidiaries that were determined to be VIEs \| reinsurer	1	1
Ownership interest through an affiliate (as a percent)	100.00%
Investment to which risk of loss related to the VIE is limited	$ 10,000
Payments made to guarantee	$ 0
Steel City
Variable Interest Entities
Ownership interest through an affiliate (as a percent)	100.00%
Investment to which risk of loss related to the VIE is limited	$ 10,000
Payments made to guarantee	$ 0

Represents the number of wholly owned subsidiaries which were determined to be variable interest entities.

No definition available.

Name:	plico_NumberOfWhollyOwnedSubsidiariesWhichWereDeterminedToBeVIE
Namespace Prefix:	plico_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Represents the amount of payments made or required to be made related to the guarantee.

+ References

No definition available.

+ Details

Name:	plico_VariableInterestEntityPayments
Namespace Prefix:	plico_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The reporting entity's maximum amount of exposure to loss as a result of its involvement with the Variable Interest Entity (VIE).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph b
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5728-111685

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=d3e5747-111685

+ Details

Name:	us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_VariableInterestEntityLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=77990344&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=plico_RedMountainLLCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=plico_SteelCityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: